Add pxe_snmp driver to list of enabled drivers
Add pxe_snmp driver to list of enabled drivers

It is now validated in ironic that the driver that will be used
for deployment is in the list of enabled drivers. pxe_snmp is not
in this list by default.

Change-Id: I9b8f55c67b5a9bdee062b0821ba091ff6dff1b3b

openstack-infra/project-config,openstack-infra/project-config